Automatic analyzer

ABSTRACT

An automatic analyzer having a smaller size, allowing a larger number of reagents to be loaded, and having a higher processing capability. Reagent disks are disposed inside and outside a reaction disk. Reagent probes are disposed to be able to suck reagents from the reagent disks and eject the reagents at common positions. A plurality of reagent probes are alternately accessed one by one to each of the reagent disks per cycle. Each reagent probe comprises two arms rotatable independently of each other so that the reagent probe is able to access a plurality of points and interference between the plurality of reagent probes can be avoided. A first reagent and a second reagent can be loaded on each of the reagent disks, and the number of loadable reagents can be increased without enlarging an overall system size. Thus, an automatic analyzer having a shorter cycle time and a higher processing capability can be realized.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an automatic analyzer for automaticallyanalyzing various components of blood, etc., and more particularly to anautomatic analyzer capable of loading a larger number of reagents andrealizing a higher throughput per unit time.

2. Description of the Related Art

An automatic analyzer for automatically analyzing living samples, suchas blood, and outputting analysis results is essential for carrying outanalysis with high efficiency in, e.g., large-, medium- and small-scaledhospitals handling a large number of patients, as well as in a cliniccenter carrying out analysis under contract with those hospitals anddoctor's offices.

In that type of automatic analyzer, it is demanded that the system ismore compact, is able to perform more kinds of analysis, and has ahigher processing speed. To satisfy those demands, various types ofautomatic analyzers have been proposed so far. For example, PatentDocument 1; JP,A 5-10957 discloses an automatic analyzer comprising tworeagent disks capable of loading reagents in concentric arrangement, andreagent probes independently movable corresponding to concentric rows ofreagent containers. In other words, Patent Document 1 is intended toincrease the number of loadable reagents by arranging two reagent disksin concentric relation, and to avoid a reduction of the processing speedby providing reagent probes to be independently movable corresponding torespective rows of reagent containers.

With that disclosed related art, however, because a plurality of reagentprobes accessing the row of reagent containers on one reagent disk areoperated to rotate about the same rotary shaft, reagents sucked fromreagent containers on the same reagent disk can be dispensed just into areaction cuvette located on the same dispensing position on a reactiondisk. Also, reagents sucked from reagent containers on the differentreagent disks can be dispensed only to respective positions on thereaction disk different from each other. Thus, analysis cannot beperformed at a high speed in random combinations.

To overcome such a problem, Patent Document 2; JP,A 2004-45112 disclosesan automatic analyzer including a reagent dispensing probe and providedwith a mechanism capable of reciprocally moving the probe not only alonga rail interconnecting a plurality of reagent disks, but also in adirection perpendicular to the rail. In other words, Patent Document 2is intended to enlarge an area where the reagent dispensing probe ismovable, thereby widening an area allowing reagent containers andreaction cuvettes to be accessible therein and increasing the degree offreedom in dispensing operations. Further, the processing speed isincreased by providing a plurality of reagent dispensing probes whichare reciprocally movable along the rail or providing a plurality ofrails.

SUMMARY OF THE INVENTION

With the related art disclosed in Patent Document 2, however, since therail must be laid to extend over the area where the reagent dispensingprobe is movable, a frame for supporting the rail is necessary and theframe is required to have a high mechanical strength.

In particular, when a high processing speed is required, a plurality ofreagent dispensing probes are disposed and a plurality of rails areprovided on the frame. Then, the plurality of the reagent dispensingprobes are operated at high speeds at the same time. This gives rise toa problem that vibrations generated especially at start and stop of theoperation are propagated to other reagent dispensing probes through therails, thus resulting in scattering of the reagent, a reduction ofdispensing accuracy, and other troubles.

To suppress the generated vibrations, the mechanical strength of theframe must be increased, but an increase of the mechanical strengthgives rise to another problem of increasing the frame size. Usually, themechanical strength of the frame is low when the frame is supported in acantilevered manner, and is increased by connecting frame members into abox-like structure. However, because the frame is disposed to so asbridge the plurality of reagent disks and the reaction disk loading thereaction cuvettes on it, the frame having a box-like shape is arrangedin covering relation to the reagent disks, and operations of replacingreagents set on the reagent disks are very difficult to carry out. In asystem with a high processing capability, reagents are consumed at highrates and the frequency of replacing the reagents is increased. For thatreason, a difficulty in the operations of replacing reagents is aserious problem.

Also, with the structure in which the reagent dispensing probe isdisposed on the rail, the rail length must be prolonged in proportion toenlargement of the area where the reagent dispensing probe is movable,thus resulting in the increased cost.

Further, even in the case providing a plurality of reagent dispensingprobes, there occurs a problem that, for example, when two reagentdispensing probes are operated so as to simultaneously access twopositions close to each other, only one reagent dispensing probe can beoperated in practice because the rails mutually obstruct the respectiveprobe operations.

With the view of overcoming the problems mentioned above, the presentinvention is constituted as follows.

In an automatic analyzer comprising a reagent disk on which a pluralityof reagent containers are arranged along a circumference, a reactiondisk on which a plurality of reaction cuvettes are arranged along acircumference, and a mechanism for causing reactions between reagentscontained in the reagent containers and samples in the reaction cuvettesand analyzing the reactions developed in the reaction cuvettes, theautomatic analyzer includes a plurality of reagent disks and a reagentdispensing probe for sucking the reagent from the reagent container andejecting the sucked reagent into the reaction cuvette, the reagentdispensing probe comprising a first arm operated to rotate about a firstrotary shaft and a second arm operated to rotate about a second rotaryshaft disposed on the first arm, the first arm and the second arm beingrotatable independently of each other. With those features, the reagentdispensing probe is able to access a wider area, any obstacle such as asupport structure is not present above the reagent disks, andmaintenance operations such as reagent replacement can be facilitated.The reagent dispensing probe comprising the first arm and the secondarm, which are rotatable independently of each other, may be disposed inplural for the purpose of obtaining an even higher processingcapability. In this case, since the plurality of reagent dispensingprobes can be independently mounted in the automatic analyzer, stabledispensing performance can be ensured without suffering from adverseinfluences such as reagent scattering and a reduction of the dispensingperformance caused by vibrations generated with operations of one ormore other reagent dispensing probes.

Also, the area accessible by the reagent dispensing probe is given as anarea within the radius of rotation of the second arm about a point on apath along which the center of rotation of the second arm rotates, thecenter of rotation of the second arm being located in the first arm.Therefore, the area accessible by the reagent dispensing probe can beeasily set depending on applications by changing respective lengths ofthe first arm and the second arm.

Further, in the case operating a plurality of reagent dispensing probes,even when the probes are required to access places close to each other,interference between those probes can be avoided by shifting theoperation timings of the first arm and the second arm of the probe. As aresult, the dispensing performance can be maximally utilized withoutbeing restricted by operations of the other mechanism components unlikethe above-described related art using rails.

Thus, according to the present invention, two reaction disks eachloading a first reagent and a second reagent thereon are disposed, andeither reagent is sucked by only one reagent dispensing probe fromeither reagent disk per cycle. The reagent dispensing probe is made uptwo arms rotatable independently of each other so that one probe is ableto access a plurality of points and interference between a plurality ofreagent dispensing probes can be avoided. Consequently, it is possibleto provide an automatic analyzer capable of loading a larger number ofreagents and having a higher processing capability per unit time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an automatic analyzer according to afirst embodiment; and

FIG. 2 is a plan view of the automatic analyzer according to the firstembodiment;

FIG. 3 is an explanatory view of a principal part of the firstembodiment;

FIG. 4 is a schematic view showing the construction of a reagentdispensing probe in the first embodiment;

FIG. 5 is a schematic view showing the construction of a reagentdispensing probe in a second embodiment;

FIG. 6 is an explanatory view for explaining the operation of theautomatic analyzer according to the first embodiment;

FIG. 7 is an explanatory view for explaining the operation of theautomatic analyzer according to the first embodiment;

FIG. 8 is an explanatory view for explaining the operation of theautomatic analyzer according to the first embodiment;

FIG. 9 is an explanatory view for explaining the operation of theautomatic analyzer according to the first embodiment;

FIG. 10 is an explanatory view for explaining the operation of theautomatic analyzer according to the first embodiment;

FIG. 11 is an explanatory view for explaining the operation of theautomatic analyzer according to the first embodiment;

FIG. 12 is an explanatory view for explaining the operation of theautomatic analyzer according to the first embodiment;

FIG. 13 is a schematic view showing the construction of a reagent diskin a second embodiment;

FIG. 14 is an explanatory view for explaining the operation of avoidinginterference between the reagent dispensing probes; and

FIG. 15 is an explanatory view for explaining the operation of avoidinginterference between the reagent dispensing probes.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will be described below withreference to the drawings. FIGS. 1 and 2 are respectively a perspectiveview and a plan view of an automatic analyzer according to a firstembodiment of the present invention.

A total number 54 of reaction cuvettes 35 are arranged on a reactiondisk 36 along its circumference, the reaction disk 36 being disposed ona casing 62. A reagent disk 42 is disposed inside the reaction disk 36,and a reagent disk 41 is disposed outside the reaction disk 36. Aplurality of reagent containers 40 are loadable on each of the reagentdisks 41, 42 along its circumference. One reagent container 40 containstwo kinds of reagents. A conveyer mechanism 12 for moving a rack 11 withsample containers 10 loaded thereon is installed near the reaction disk36. Reagent (dispensing) probes 20, 21, 22 and 23 are disposed betweenthe reagent disk 41 and the reagent disk 42 to be rotatable inrespective planes and movable in the vertical direction. The detailedconstruction of each reagent probe will be described later.

The reagent probes 20, 21, 22 and 23 are each connected to a reagentpump 24. Between the reaction disk 36 loading the reaction cuvettes 35thereon and the conveyer mechanism 12, sample probes 15, 16 are disposedto be rotatable in respective planes and movable in the verticaldirection. The sample probes 15, 16 are each connected to a sample pump14. Around the reaction disk 36, there are arranged mixing units 30, 31,a light source 50, an optical detector 51, and a cuvette washingmechanism 45. The cuvette washing mechanism 45 is connected to a washingpump 46.

Washing ports 54 are disposed within respective areas where the sampleprobes 15, 16, the reagent probes 20, 21, 22 and 23, and the mixingunits 30, 31 are movable.

The sample pump 14, the reagent pump 24, the washing pump 46, theoptical detector 51, the reaction disk 36 loading the reaction cuvettes35 thereon, the reagent disk 41, the reagent probes 20, 21, 22 and 23,and the sample probes 15, 16 are each connected to a controller 60.

As shown in FIG. 3, a sample dispensing position, a first timing reagentdispensing position, a second timing reagent dispensing position, athird timing reagent dispensing position, mixing positions, a measuringposition, and washing positions are decided along a circumference of thereaction disk 36. Also, the reaction disk 36 is operated to rotatecounterclockwise in each stroke of 11 pitches and to stop per presetunit cycle time in a repeated way. In other words, the reaction cuvettelocated at a position 1 in a certain cycle is advanced to a position 2in a next cycle.

FIG. 4 shows one example of the construction of the reagent dispensingprobe in the first embodiment of the present invention.

The reagent dispensing probe is operated in combination of probeoperations in the horizontal direction and the vertical direction. Theoperation in the horizontal direction is performed in combination ofrotations of a first arm 74 and a second arm 79.

The first arm 74 is rotated in such a manner that a rotation drive forceof a first arm driving motor 70 is transmitted to a pulley 72 through abelt 71 and then transmitted to the first arm 74 through a hollow shaft73 coupled to the pulley 72.

The second arm 79 is rotated in such a manner that a rotation driveforce of a second arm driving motor 75 is transmitted to a shaft 76which is directly coupled to a shaft of the motor 75 and is disposed toextend through the hollow shaft 73, and then transmitted through a belt77 to a shaft 78 which is disposed to penetrate the first arm 74 andserves as a center of the rotation of the second arm 79.

Arm vertical movements are performed as follows. The rotation of avertical operation driving motor 80 is converted to a linear motionthrough combination of a pulley and a belt 81. A slider 82 is fixed atits one end to the belt 81 and coupled at its other end to the shaft 73.As a result, the first and second arms are vertically moved at the sametime.

An area accessible by the reagent dispensing probe is represented by acircular area 85.

FIG. 5 shows another example of the construction of the reagentdispensing probe in a second embodiment of the present invention.

The first arm 74 is rotated in the same manner as described above, whilethe second arm 79 is rotated by a second arm driving motor 75 disposedinside the first arm 74. Further, arm vertical movements are performedsuch that a ball screw 83 directly coupled to the vertical operationdriving motor 80 converts the motor rotation to a linear motion, and aslider 82 coupled to a nut of the ball screw 83 is vertically moved.Although the shaft 73 is not always required to be hollow in thisexample, it is preferably hollow from the viewpoint of weight reduction.

The example shown in FIG. 4 is advantageous in that, because the motors70, 75 and 80 are all disposed below an upper surface 84 of a tablecover housing the automatic analyzer therein, wiring for the motors 70,75 and 80 is laid below the upper surface 84 of the table cover and aneat external appearance is obtained. On the other hand, the exampleshown in FIG. 5 is advantageous in that, because the second arm drivingmotor 75 is disposed inside the first arm 74 and the shaft 76 shown inFIG. 4 can be dispensed with, the number of necessary parts is cut andthe weight of vertically moving parts is reduced, thus resulting in asmaller torque required for the vertical operation driving motor 80.

Though not shown, the second arm driving motor 75 may be disposed at atop of the shaft 78 about which the second arm 79 is rotated, and may bedirectly connected to the shaft 78. In this case, the belt 77 is nolonger required and the number of necessary parts can be further cut.

Using the automatic analyzer thus constructed, the analysis is performedin the sequence described below.

A sample to be analyzed, such as blood, is put in the sample container10. The sample container 10 is placed on the rack 11 and then conveyedby the conveyer mechanism 12. Thereafter, the sample probe 15 sucks asample in amount required for a first test from one of the samplecontainers 10 located at a particular position (FIG. 2). Then, in afirst cycle, a predetermined amount of the sample is ejected from thesample probe 15 into one reaction cuvette 35 located at a position 1(FIG. 3) on the reaction disk 36. During that period, the reagent probe20 sucks a predetermined amount of a first reagent corresponding to thefirst test from one of the reagent container 40 loaded on the reagentdisk 41 (FIG. 6).

In a second cycle, the relevant reaction cuvette is advanced to aposition 2 on the reaction disk 36. At that position 2, the reagentprobe 20 ejects the predetermined amount of the first reagent into therelevant reaction cuvette. During that period, the sample probe 15 iswashed (FIG. 7).

In a third cycle, the reagent and the sample in the relevant reactioncuvette are mixed by the mixing unit 30 at a position 3 on the reactiondisk 36. During that period, the reagent probe 20 is washed (FIG. 8).

In a fourth cycle, while the relevant reaction cuvette is rotated to aposition 4 on the reaction disk 36, it passes between the light source50 and the optical detector 51 so that optical measurement is carriedout. During the rotation of the reaction disk 36, the mixing unit 30 iswashed in the washing port 54 (FIG. 9).

In each of ninth, 14th, 19th, 24th, 29th, 34th and 39th cycles, theoptical measurement is carried out in a similar manner.

When the first test requires a second reagent to be dispensed at thesecond timing, the reagent probe 22 sucks, in a 16th cycle, the secondreagent from one of the reagent containers 40 loaded on the reagent disk41 (FIG. 10) and then ejects, in a 17th cycle, the second reagent intothe relevant reaction cuvette located at a position 17 on the reactiondisk 36 (FIG. 11). In an 18th cycle, the mixing unit 31 mixes the liquidin the relevant reaction cuvette located at a position 18 on thereaction disk 36. During that period, the reagent probe 22 is washed(FIG. 12).

When the first test requires the second reagent to be dispensed at thethird timing, the reagent probe 22 sucks, in a 26th cycle, the secondreagent from one of the reagent containers 40 loaded on the reagent disk41 and then ejects, in a 27th cycle, the second reagent into therelevant reaction cuvette located at a position 27 on the reaction disk36. In a 28th cycle, the mixing unit 31 mixes the liquid in the relevantreaction cuvette located at a position 28 on the reaction disk 36.During that period, the reagent probe 22 is washed.

After dispensing the second reagent, mixing the liquid and repeating theoptical measurement, the cuvette washing mechanism 45 sucks the liquidin the relevant reaction cuvette and then pours a washing liquid intothe relevant reaction cuvette at a position 44 or 49 on the reactiondisk 36 in a 44th or 49th cycle. Further, the washing liquid iscompletely sucked in a 54th cycle.

Results of the optical measurements performed plural times using theoptical detector 51 are sent to the controller 60 in whichconcentrations of items to be measured in the first test are calculated.

A second test is performed as follows. In a first cycle, the sampleprobe 16 sucks a sample in amount required for the second test from thesample container 10 located at a particular position (FIG. 6). Then, ina second cycle, a predetermined amount of the sample is ejected from thesample probe 16 into one reaction cuvette 35 located at the position 1on the reaction disk 36. During that period, the reagent probe 21 sucksa predetermined amount of a first reagent corresponding to the secondtest from one of the reagent containers 40 loaded on the reagent disk 42(FIG. 7).

In a third cycle, the relevant reaction cuvette is advanced to theposition 2 on the reaction disk 36. At that position 2, the reagentprobe 21 ejects the predetermined amount of the first reagent into therelevant reaction cuvette. During that period, the sample probe 16 iswashed (FIG. 8).

In a fourth cycle, the reagent and the sample in the relevant reactioncuvette are mixed by the mixing unit 30 at the position 3 on thereaction disk 36. During that period, the reagent probe 21 is washed(FIG. 9).

In a fifth cycle, while the relevant reaction cuvette is rotated to theposition 4 on the reaction disk 36, it passes between the light source50 and the optical detector 51 so that optical measurement is carriedout. During the rotation of the reaction disk 36, the mixing unit 30 iswashed in the washing port 54.

In each of tenth, 15th, 20th, 25th, 30th, 35th and 40th cycles, theoptical measurement is carried out in a similar manner.

When the second test requires a second reagent to be dispensed at thesecond timing, the reagent probe 23 sucks, in a 17th cycle, the secondreagent from one of the reagent container 40 loaded on the reagent disk42 (FIG. 11) and then ejects, in an 18th cycle, the second reagent intothe relevant reaction cuvette located at a position 18 on the reactiondisk 36 (FIG. 12). In a 19th cycle, the mixing unit 31 mixes the liquidin the relevant reaction cuvette located at the position 18 on thereaction disk 36. During that period, the reagent probe 23 is washed(FIG. 9).

When the second test requires the second reagent to be dispensed at thethird timing, the reagent probe 23 sucks, in a 27th cycle, the secondreagent from one of the reagent container 40 loaded on the reagent disk42 and then ejects, in a 28th cycle, the second reagent into therelevant reaction cuvette located at the position 27 on the reactiondisk 36. In a 29th cycle, the mixing unit 31 mixes the liquid in therelevant reaction cuvette located at the position 28 on the reactiondisk 36. During that period, the reagent probe 23 is washed.

After dispensing the second reagent, mixing the liquid and repeating theoptical measurement, the cuvette washing mechanism 45 sucks the liquidin the relevant reaction cuvette and then pours a washing liquid intothe relevant reaction cuvette at the position 44 or 49 on the reactiondisk 36 in a 45th or 50th cycle. Further, the washing liquid iscompletely sucked in a 55th cycle.

Results of the optical measurements performed plural times using theoptical detector 51 are sent to the controller 60 in whichconcentrations of items to be measured in the second test arecalculated.

In a third test, the same steps as those in the first test are repeatedwith a delay of 2 cycles. In a fourth test, the same steps as those inthe second test are repeated with a delay of 2 cycles. Thereafter, thosetwo types of test sequences are successively repeated through similarsteps, whereby concentrations of items to be measured for the sample areanalyzed with a plurality of tests.

Thus, with this embodiment, the reagent probe 20 accesses the reagentdisk 41 to suck the reagent from it in an odd-numbered cycle, and thereagent probe 22 accesses the reagent disk 41 to suck the reagent fromit in an even-numbered cycle. Therefore, those two probes are avoidedfrom simultaneously accessing the reagent disk 41 in the same cycle.Likewise, the reagent probe 23 accesses the reagent disk 42 to suck thereagent from it in an odd-numbered cycle, and the reagent probe 21accesses the reagent disk 42 to suck the reagent from it in aneven-numbered cycle. Therefore, those two probes are avoided fromsimultaneously accessing the reagent disk 41 in the same cycle. As aresult, it is possible to shorten the cycle time and to increase thenumber of samples analyzable in a certain time.

Also, since only one reagent probe sucks the reagent from thecorresponding reagent disk during one cycle, a time for sucking thesample and a time for moving the probe can be prolonged, and the reagentcan be stably dispensed with high accuracy.

Further, since two reagent disks are independently rotatable and onlyone reagent probe sucks the reagent from the corresponding reagent diskin one cycle, combinations of reagents to be sucked for the same testcan be freely selected and analysis can be realized with a highprocessing capability while being adapted for irregular combination ofanalysis items.

Moreover, with this embodiment, the first and second reagents used ineach odd-numbered test are both sucked from the reagent disk 41, and thefirst and second reagents used in each even-numbered test are bothsucked from the reagent disk 42. Stated another way, the first andsecond reagents used for the same analysis item can be put on the samereagent disk in one side. Thus, since the reagents for each analysisitem are replaced with respect to the corresponding reagent disk ineither side, a time and labor required for replacing the reagents can becut and errors in the replacing operations can be reduced.

With this embodiment, two kinds of reagents can be put in the reagentcontainer 40. Therefore, the first reagent and the second reagent foruse in one analysis item can be put in one reagent container 40, thusallowing the first reagent and the second reagent to be replaced at atime. As a result, a time and labor required for replacing the reagentscan be cut and errors in the replacing operations can be reduced.

With this embodiment, since the reagent probe 20 accesses the firsttiming reagent dispensing position on the reaction disk 36 in aneven-numbered cycle and the reagent probe 21 accesses it in anodd-numbered cycle for ejecting the first reagent, those two probes areavoided from simultaneously accessing the first timing reagentdispensing position in one cycle. Likewise, since the reagent probe 22accesses the second or third timing reagent dispensing position on thereaction disk 36 in an odd-numbered cycle and the reagent probe 23accesses it in an even-numbered cycle for ejecting the second reagent,those two probes are avoided from simultaneously accessing the second orthird timing reagent dispensing position in one cycle. Also, since thefirst timing reagent dispensing position, the second timing reagentdispensing position, and the third timing reagent dispensing positionare located away from each other, the probes are able to access thosepositions at the same time. This means that just one period for ejectingthe reagent is required in each cycle. As a result, it is possible toshorten the cycle time and to increase the number of samples analyzablein a certain time.

In addition, since only one probe ejects the reagent at the sameposition in one cycle, a time required for ejecting the reagent can beprolonged and the reagent can be ejected with high accuracy and highreproducibility. Accordingly, the reagent can be dispensed in anaccurate amount, and the analysis can be performed with high accuracy.

With this embodiment, the reagent probes 20 and 23 suck the reagents inodd-numbered cycles and eject the reagents in even-numbered cycles,while the reagent probes 21 and 22 suck the reagents in even-numberedcycles and eject the reagents in odd-numbered cycles. Therefore, eachprobe is just required to perform the steps of sucking the reagent,ejecting the sucked reagent, and washing itself during a time of twocycles. As a result, the operation time can be set with a sufficientmargin, and stable operation can be ensured.

Still further, since a longer operation time is set for each reagentprobe, a range over which the probe is movable can be increased and thesize of the reagent disk can be enlarged correspondingly. Therefore,more kinds of reagents required for analyses can be loaded on onereagent disk at the same time.

With this embodiment, since the eject position of the reagent probe 20and the eject position of the reagent probe 21 are matched with eachother, the reagents can be dispensed at equivalent timing regardless offrom which one of the probes the first reagent is ejected. Accordingly,the reaction process can be analyzed under identical conditions.

With this embodiment, since the reagent probes 22 and 23 can access thesecond timing reagent dispensing position and the third timing reagentdispensing position in common to eject the second reagent, it ispossible to analyze plural kinds of reactions in which the secondreagent is mixed at different timings, and to increase the number ofkinds of analyzable items.

Furthermore, since the eject positions are in common between the reagentprobes 22 and 23, the analysis can be performed under identicalconditions.

Since the reagent disk 41 and the reagent disk 42 are disposedrespectively outside and inside the reaction disk 36 with the reagenteject positions on the reaction disk located between them, those tworeagent disks can be installed at a shorter distance therebetween.

Also, since the reagent disks 41 and 42 are installed close to eachother, the distance to each of the common reagent eject positions isshortened and so is the distance over which the reagent probe is moved.It is hence possible to shorten the cycle time and to increase thenumber of samples analyzable in a certain time.

With this embodiment, since the sample probes 15 and 16 alternatelyrepeat the steps of sucking the sample and ejecting it, only one sampleprobe accesses either the sample container 10 or the reaction cuvette35. It is hence possible to shorten the cycle time and to increase thenumber of samples analyzable in a certain time.

Further, since the sample probes 15 and 16 are each just required toperform the steps of sucking the sample, ejecting the sucked sample, andwashing itself during two cycles, the operation time for dispensing andprobe movement can be set with a sufficient margin. As a result, thereagent can be dispensed in a higher accurate amount, and the analysiscan be performed with higher accuracy.

With this embodiment, in a test using a sample dispensed by the sampleprobe 15, a first reagent is dispensed by the reagent probe 20 from thereagent disk 41, and a second reagent is dispensed by the reagent probe22 from the reagent disk 41. In a test using a sample dispensed by thesample probe 16, a first reagent is dispensed by the reagent probe 21from the reagent disk 42, and a second reagent is dispensed by thereagent probe 23 from the reagent disk 42. Accordingly, the sample probe15, the reagent disk 41, the reagent probe 20, and the reagent probe 22constitute a first set, while the sample probe 16, the reagent disk 42,the reagent probe 21, and the reagent probe 23 constitute a second set.These sets are independent of each other such that one of the sets is inno way combined with the other. Therefore, calibration using the sampleprobe 15, the reagent probe 20 and the reagent probe 22 is just requiredfor each of the analysis items corresponding to the reagents loaded onthe reagent disk 41, and calibration using the sample probe 16, thereagent probe 21 and the reagent probe 23 is just required for each ofthe analysis items corresponding to the reagents loaded on the reagentdisk 42. Thus, since only the calibration is required for each set, itis possible to reduce the number of calibrations to be performed, toavoid wasteful use of the reagents and time, and to eliminatedifferences in analysis results caused by different characteristicsamong the probes.

If the first timing of reagent dispensing is shifted from the second orthird timing of reagent dispensing by even-numbered cycles, there is apossibility that the first reagent and the second reagent must be suckedfrom the same reagent disk in one cycle. In contrast, according to thisembodiment, the first timing of reagent dispensing is shifted from thesecond or third timing of reagent dispensing by odd-numbered cycles, thefirst reagent being sucked from one reagent disk, the second reagentbeing sucked form the other reagent disk, the first reagent and thesecond reagent being alternately sucked with each other.

Mores specifically, with this embodiment, since a total number 54 ofreaction cuvettes 35 are loaded and each reaction cuvette is rotated instroke of 11 pitches per cycle, the reaction cuvette is rotated over 1rotation plus 1 pitch in five cycles. Therefore, one reaction cuvettelocated at a certain position on the reaction disk is moved to aposition adjacent to the certain position, i.e., a position shifted 1pitch from it, after 5 cycles. If the reaction cuvette is rotated over 1rotation plus 1 pitch in even-numbered cycles, one reaction cuvettelocated at a certain position on the reaction disk is moved to aposition adjacent to the certain position, i.e., a position shifted 1pitch from it, after the even-numbered cycles. In this case, thereaction cuvette is moved to one of successive positions in turn at atime difference corresponding to the even-numbered cycles. If it isattempted in such a case to separately perform the timing of dispensingthe first reagent and the timing of dispensing the second reagentrespectively in an even-numbered cycle and an odd-numbered cycle, theeject positions of the first reagent and the second reagent are locatedapart away from each other, and the reagent probes must be installed inpositions apart away from each other correspondingly. In contrast,according to this embodiment, since the reaction cuvette is rotated over1 rotation plus 1 pitch in odd-numbered cycles, the eject positions ofthe first reagent and the second reagent can be set close to each other,and the overall system size can be reduced. A similar effect can also beobtained when the reaction cuvette is rotated over 1 rotation minus 1pitch in odd-numbered cycles.

In addition, with this embodiment, since the position of the reactioncuvette is shifted 1 pitch in odd-numbered cycles, a row of reactioncuvettes for which measurement cannot be performed because of passingthe position for the measurement by the optical detector 51 in anaccelerated or decelerated state are continued at successive timings.Those successive timings can be set in match with the timing of washingthe reaction cuvette, which is in no way related to the measurement ofthe reaction process. It is therefore possible to continuously performthe analysis without including the timing at which the measurement islacked during the reaction process, and to carry out the analysis on avariety of items ranging from an item requiring a short time reaction toan item requiring a long time reaction.

In another example of use, in the automatic analyzer having the sameconstruction as that shown in FIGS. 1, 2 and 3, the reaction disk 36 isrotated clockwise in each stroke of 43 pitches per cycle. In thisexample, the reaction cuvette located at the position 1 on the reactiondisk 36 is similarly moved to the position 2 on the reaction disk 36 ina next cycle. With this example, since the reaction cuvette passes theposition of the optical detector 51 four times in 5 cycles, the numberof measurements is increased and the analysis accuracy can be increased.

FIG. 13 shows a reagent disk according to a second embodiment of thepresent invention. In this second embodiment, reagent containers 40 arearranged on a reagent disk 41 in dual circumferential rows. Similarly,reagent containers 40 are arranged on a reagent disk 42 in dualcircumferential rows. Since this embodiment enables a larger number ofreagents to be arranged on a smaller reagent disk, the number ofanalyzable items can be increased without enlarging the overall systemsize.

One example of operation for avoiding interference between the reagent(dispensing) probes will be described below with reference to FIG. 12.In the state of FIG. 12, the reagent probe 20 ejects the first reagentto one corresponding reaction cuvette, and the reagent probe 23 ejectsthe second reagent to another corresponding reaction cuvette. In a nextcycle, the reagent probe 20 and the reagent probe 23 are returned torespective washing ports 54 for washing of the reagent probes. Themovement of each reagent probe to the washing port 54 is ideallyperformed by moving the first arm 74 and the second arm 79 at the sametime for the purpose of minimizing the required time. However, becausethe reagent probe 21 is present near a path along which the reagentprobe 20 is returned to the washing port 54, interference between thosetwo reagent probes must be avoided. In such a case, only the first arm74 of the reagent probe 20 is moved to a position where the second arm79 does not interfere with the reagent probe 21 even when the second arm79 is moved (FIG. 14). Then, the second arm 79 is moved for return tothe washing port 54 (FIG. 15). On the other hand, there is no obstaclenear a path along which the reagent probe 23 is returned to the washingport 54. Therefore, the reagent probe 23 can be returned to the washingport 54 by operating the first arm 74 and the second arm 79 at the sametime (FIG. 15). As shown in this example, since the first arm 74 and thesecond arm 79 are operated independently of each other in the reagentprobe of the present invention, the operation timing can be freelychanged. Therefore, the path of the probe movement can be changed so asto avoid interference between the mechanism components, for example,when the reagent probes are moved to any points close to each other.

Further, shifting the operation timings of the first arm 74 and thesecond arm 79 gives rise to another effect of suppressing vibrationscaused at a probe end. If the first arm 74 and the second arm 79 areoperated to start at the same time and to stop at the same time, avibration caused upon stop of the first arm 74 and a vibration causedupon stop of the second arm 79 are added to produce a larger vibrationat the prove end when the probe is stopped. By operating the first arm74 at earlier timing and operating the second arm 79 at later timing,for example, as in the above-mentioned example, only the second arm 79is stopped and therefore the vibration caused at the prove end can bereduced at the time when the entire operation of the probe comes to anend. As a result, scattering of the reagent can be prevented.

1. An automatic analyzer comprising: a plurality of reagent disk onwhich a plurality of reagent containers are arranged along acircumference; a reaction disk on which a plurality of reaction cuvettesare arranged along a circumference; a mechanism for causing reactionsbetween reagents contained in said reagent containers and samples insaid reaction cuvettes and analyzing the reactions developed in saidreaction cuvettes; and, a reagent dispensing probe for sucking thereagent from said reagent container and ejecting the sucked reagent intosaid reaction cuvette, said reagent dispensing probe including a firstarm operated to rotate about a first rotary shaft and a second armoperated to rotate about a second rotary shaft disposed on said firstarm, said first arm and said second arm being rotatable independently ofeach other.
 2. The automatic analyzer according to claim 1, wherein saidsecond rotary shaft is disposed nearly at a fore end of said first arm.